JP3019642B2 - Pressure-sensitive recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pressure-sensitive recording material using a fluoran compound as an electron-donating leuco dye.

[0002]

2. Description of the Related Art A pressure-sensitive recording material utilizing a color-forming reaction between an electron-donating leuco dye (hereinafter referred to as "leuco dye") and an electron-accepting developer (hereinafter referred to as "developer"), particularly a pressure-sensitive recording medium having a black recorded image. Recording media are widely used. The leuco dye itself is substantially colorless, but forms a color by reacting with a developer. At present, a fluoran compound represented by the general formula (I) of Formula 1 (wherein X represents a substituted amino group) is mainly used as a leuco dye for a pressure-sensitive recording material having a black recorded image. I have.

[0003]

Embedded image

In a fluoran compound represented by the general formula (I), the absorption maximum on the long wavelength side generally shifts to a shallow color by light. Therefore, a black recording image of a pressure-sensitive recording material using the fluoran compound is light. There is a disadvantage that the color changes to red. Accordingly, there is a demand for a pressure-sensitive recording medium in which a black recorded image does not turn red by light.

Japanese Unexamined Patent Publication (Kokai) No. 63-192777 discloses a compound represented by the following general formula (II) (wherein Y is a substituted amino group, R ¹ ,
R ² individually represents a lower alkyl group. ) Is disclosed, and it is disclosed that a black recorded image using the fluoran compound has a small red change.

[0006]

Embedded image

JP-A-1-150574 discloses a black recorded image using a fluoran compound represented by the general formula (III) of the formula (III) (wherein Z represents a substituted amino group). It discloses that the change is small.

[0008]

Embedded image

The general formula (II) or the general formula (II)
The black recorded image using the fluoran compound represented by I) has a small red change, but its color tone is represented by the general formula (I) because of the 2,6-dialkyl group on the 2-position anilino group. It is reddish than the color tone of a black recorded image using a fluoran compound. Therefore, there is a demand for a pressure-sensitive recording medium in which a black recorded image does not change color to red by light and the color tone of the black recorded image is close to pure black. SUMMARY OF THE INVENTION It is an object of the present invention to provide a pressure-sensitive recording medium in which the redness of a black recorded image due to light is small and the color tone of the black recorded image is pure black.

[0010]

The pressure-sensitive recording object of the present invention is a leuco dye having the following 2- (2)
6-dimethylanilino) -3-methyl-6-diethylaminofluoran (hereinafter referred to as compound A)
This was achieved by a pressure-sensitive recording material using together-(2,4-dimethylanilino) -3-methyl-6-diethylaminofluoran (hereinafter referred to as compound B).

[0011]

Embedded image

[0012]

Embedded image

When a leuco dye is applied to a pressure-sensitive recording medium,
In general, a leuco dye is dissolved in an encapsulating solvent and used in a state of being encapsulated in a microcapsule using a polymer compound as a film agent.
Therefore, high solubility in an encapsulating solvent is important as one of the properties required for a leuco dye for a pressure-sensitive recording medium, and it is generally considered that a solubility of 2% or more is preferable.

Compound A and compound B have a solubility of 2% or more in both KMC-113 (Kureha Chemical Industry) and SAS-296 (Nippon Petrochemical), which are practically used as encapsulating solvents. . Therefore, the combined use of compound A and compound B is extremely advantageous for producing a pressure-sensitive recording medium. The comparative measurement results of the solubility of the compound A and the compound B in the encapsulating solvent with the similar compound C and the compound D of the following [Chemical Formula 6] which differ only in the alkyl group on the amino group at the 6-position. Are shown in Table 1.

[0015]

Embedded image

[0016]

Embedded image

[Table 1] Solubility of leuco dye {Leuco dye KMC-113 SAS-296} ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Compound A 2.1% 4.2% Compound B 4.5% 5.0% or more Compound C 0.8% 1.0% Compound D 0.9% 1.2% ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ The solubility in Table 1 was measured as described below.

5 g of the leuco dye was added to 95 g of the encapsulating solvent and dissolved by heating at 100 ° C. to prepare a 5% leuco dye solution. The preparation was kept at 22 ° C. with stirring for 14 days. During that time, samples of the solution part were collected periodically,
The solubility of the leuco dye was measured by HPLC analysis using a separately prepared calibration curve. The solubility almost reached equilibrium after holding for 7 days.

In addition to using the compound A and the compound B in combination, the pressure-sensitive recording medium may be further adjusted, if necessary, for adjusting the color tone of the recorded image or adjusting the absorption wavelength range of the recorded image. One or more leuco dyes may be used in combination.

Specific examples of these leuco dyes include:
3,6-dimethoxyfluoran, 2- (3-methoxy-
4-dodecyloxystyryl) quinoline, 2- [1-
Yellow-colored leuco dyes such as (2-cyanoethyl) -2,2,4-trimethyltetrahydroquinolin-6-yl] -4-phenoxyquinazoline, 2-chloro-6-cyclohexylaminofluoran, 3-chloro-6-cyclohexyl Orange-colored leuco dyes such as aminofluoran, 2-methyl-6-cyclohexylaminofluoran, 3-methyl-6-cyclohexylaminofluoran, 1,3-dimethyl-6-diethylaminofluoran, 2-t-butyl-
6-diethylaminofluoran, 2-chloro-6-diethylaminofluoran, 2-chloro-3-methyl-6
Diethylaminofluoran, 2-methyl-6- (N-ethyl-4-methylanilino) fluoran, 8-diethylaminobenzo [a] fluoran, 3,3-bis (1-n
-Butyl-2-methyl-3-indolyl) phthalide,
Red-colored leuco dye such as 3,3-bis (1-n-octyl-2-methyl-3-indolyl) phthalide, 3,3-bis (4-diethylamino-2-ethoxyphenyl) -4
-Azaphthalide, 2-dibenzylamino-6-diethylaminofluoran, 2-dibenzylamino-4-methyl-6-diethylaminofluoran, 2-n-octylamino-6-diethylaminofluoran, 2-anilino-
6- (N-ethyl-NN-hexylamino) fluoran, 2- (N-methylanilino) -6- (N-ethyl-
Green-forming leuco dyes such as 4-methylanilino) fluoran, 3,7-bis (dimethylamino) -10-benzoylphenothiazine, 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide, 3- ( 4-diethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2
-Methyl-3-indolyl) phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methyl-3-indolyl) -4-azaphthalide, 3- (4-diethylamino-2) -Ethoxyphenyl) -3- (1-n-octyl-2-methyl-3-indolyl) -4-azaphthalide, Nn-butyl-3-
[4,4'-bis (N-methylanilino) benzhydryl] a blue-colored leuco dye such as carbazole, 2-anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-di-n- Butylaminofluoran, 2-anilino-3-methyl-6-di-n-amylaminofluoran, 2-anilino-3-methyl-6
(N-methyl-NN-propylamino) fluoran,
2-anilino-3-methyl-6- (N-ethyl-N-isobutylamino) fluoran, 2-anilino-3-methyl-6- (N-ethyl-N-isoamylamino) fluoran, 2-anilino-3- Methyl-6- (N-cyclohexyl-N-methylamino) fluoran, 2-anilino-3-methyl-6- [N-ethyl-N- (3-ethoxypropyl) amino] fluoran, 2-anilino-3-methyl -6- (N-ethyl-4-methylanilino) fluoran, 2- (3-trifluoromethylanilino) -6
Black-colored leuco dyes such as diethylaminofluoran, 3,
6-bis (dimethylamino) fluorenespiro [9,
3 ′]-6′-dimethylaminophthalide, 3- (4-diethylaminophenyl) -3- [2,2-bis (1-ethyl-2-methyl-3-indolyl) ethenyl] phthalide, 3,3- Bis [2,2-bis (1-n-butyl-2
-Methyl-3-indolyl) ethenyl] -4,5,6
7-tetrachlorophthalide, 3,3-bis [2- (4-
Dimethylaminophenyl) -2- (4-methoxyphenyl) ethenyl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [2- (4-pyrrolidinophenyl)-
2- (4-methoxyphenyl) ethenyl] -4,5
Near-infrared-absorbing leuco dyes such as 6,7-tetrachlorophthalide, 2-chloro-3-methyl-6- [4- (4-anilinoanilino) anilino] fluoran and the like.

Compound A has a weight ratio of 20 to all leuco dyes.
８０80%, more preferably 25-60%. If the weight ratio is less than 20%, the effect of Compound A on reduction of red discoloration by light of a black recorded image of a pressure-sensitive recording medium may not be expected. On the other hand, if the weight ratio exceeds 80%, the color tone of the black image recorded on the pressure-sensitive recording medium may not be adjusted to pure black.

A pressure-sensitive recording medium is disclosed, for example, in JP-B-42-201.
It can be produced by various known methods disclosed in No. 44 and the like. In general, a leuco dye solution in which a leuco dye is dissolved in an encapsulating solvent is microencapsulated by using a polymer compound as a film agent by a known encapsulation method such as a coacervation method, an interfacial polymerization method, or an in situ polymerization method. After that, it is applied to the back surface of a support such as high-quality paper, synthetic paper, plastic film, etc. to form an upper paper. On the other hand, a developer is applied to the surface of another support to prepare a lower sheet. When the upper paper and the lower paper are overlapped so that the coating surfaces are in contact with each other and pressure is applied, the capsule in the pressurized part is destroyed, and the leuco dye in the capsule reacts with the developer, and A recorded image is formed. In addition, a plurality of copy records can be obtained by inserting several sheets of middle paper coated with a developer on the front surface of the support and capsules on the back surface between the upper paper and the lower paper. Further, by applying the microcapsules of the leuco dye on the support coated with the developer, or by mixing the microcapsules and the developer and applying the mixture on the support, a single color-developing pressure-sensitive recording medium can be manufactured. .

Examples of the developer used for the pressure-sensitive recording medium include acid clay, zinc salt of a salicylic acid derivative, zinc-modified paraoctylphenol formaldehyde resin, paraphenylphenol resin and the like.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The parts indicate parts by weight.

[Example 1] Production of pressure-sensitive recording medium 2- (2,6-dimethylanilino) -3-methyl-6-
3 parts of diethylaminofluorane and 3 parts of 2- (2,4-dimethylanilino) -3-methyl-6-diethylaminofluoran were dissolved in 94 parts of SAS-296 (encapsulation solvent manufactured by Nippon Petrochemical) under heating. . 10 parts of a system modifier was added to 200 parts of water, and the pH was adjusted to 4 with an aqueous solution of caustic soda. The above solution and 20 parts of melamine formaldehyde prepolymer were added thereto, and the mixture was emulsified with a homomixer until oil droplets became 4 μm. Then, the mixture was heated to 60 ° C. with stirring and stirred for 1 hour. After cooling to room temperature, the pH was adjusted to 7.5 with 25% aqueous ammonia to prepare a capsule dispersion of the leuco dye.

The thus prepared capsule dispersion liquid 1
After 0 parts, 2 parts of flour starch and 1 part of latex were mixed well, the amount of solids applied to fine paper of 50 g / m ² basis weight was 5%.
g / m ² to form an upper sheet.

The upper paper thus formed is superimposed on the lower paper coated with the zinc-modified paraoctylphenol formaldehyde resin developer so that the coated surface is in contact with the lower paper, and when the type printing is performed, the upper paper is clearly printed on the lower paper. A pure black recorded image was formed.

Example 2 Preparation of pressure-sensitive recording medium 2- (2,6-dimethylanilino) -3-methyl-6-
3 parts of diethylaminofluorane, 3 parts of 2- (2,4-dimethylanilino) -3-methyl-6-diethylaminofluorane, 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide 1 Part and 3,3-
Bis (1-n-butyl-2-methyl-3-indolyl)
One part of phthalide was dissolved in 92 parts of SAS-296 (encapsulating solvent manufactured by Nippon Petrochemical) under heating. 10 parts of a system modifier was added to 200 parts of water, and the pH was adjusted to 4 with an aqueous solution of caustic soda. The above solution and 20 parts of melamine formaldehyde prepolymer were added thereto, and the mixture was emulsified with a homomixer until oil droplets became 4 μm. Then, the mixture was heated to 60 ° C. with stirring and stirred for 1 hour. After cooling to room temperature, the pH was adjusted to 7.5 with 25% aqueous ammonia to prepare a capsule dispersion of the leuco dye. After 10 parts of the capsule dispersion thus prepared, 2 parts of flour starch and 1 part of latex are mixed well, the mixture is coated on a high-quality paper having a basis weight of 50 g / m ^{2 so} that the solid content is 5 g / m ^2. And made the upper paper.

The upper sheet created in this way is
When the lower paper coated with zinc di (1-phenylethyl) salicylate was overlapped with the coated surface so as to be in contact with the lower paper and type-printed, a clear pure black recorded image was formed on the lower paper.

Example 3 Preparation of pressure-sensitive recording medium 2- (2,6-dimethylanilino) -3-methyl-6-
3 parts of diethylaminofluoran, 3 parts of 2- (2,4-dimethylanilino) -3-methyl-6-diethylaminofluoran, 3,3-bis (4-diethylamino-2-ethoxyphenyl) -4-azaphthalide 3 Part and 3,3
One part of bis- (1-n-butyl-2-methyl-3-indolyl) phthalide was dissolved in 115 parts of SAS-296 (encapsulated solvent manufactured by Nippon Petrochemical) under heating. Water 200
To 10 parts of a system modifier, pH 4 with aqueous sodium hydroxide solution.
And The above solution and 20 parts of melamine formaldehyde prepolymer were added thereto, and the mixture was emulsified with a homomixer until oil droplets became 4 μm. Then, with stirring, 60
C. and stirred for 1 hour. After cooling to room temperature, the pH was adjusted to 7.5 with 25% aqueous ammonia to prepare a capsule dispersion of the leuco dye.

The capsule dispersion liquid 1 thus prepared
After 0 parts, 2 parts of flour starch and 1 part of latex were mixed well, the amount of solids applied to fine paper of 50 g / m ² basis weight was 5%.
g / m ² to form an upper sheet.

The upper sheet prepared in this way is
When the lower paper coated with zinc di (1-phenylethyl) salicylate was overlapped with the coated surface so as to be in contact with the lower paper and type-printed, a clear pure black recorded image was formed on the lower paper. This recorded image was adapted for OCR reading using a wavelength of 650 nm.

Example 4 Preparation of pressure-sensitive recording medium 2- (2,6-dimethylanilino) -3-methyl-6-
3 parts of diethylaminofluoran, 3 parts of 2- (2,4-dimethylanilino) -3-methyl-6-diethylaminofluoran, 3,3-bis [2,2-bis (1-n-butyl-2- Methyl-3-indolyl) ethenyl] -4,
5,6,7-tetrachlorophthalide 3 parts and 3,3-
Bis (1-n-butyl-2-methyl-3-indolyl)
One part of phthalide was dissolved in 115 parts of SAS-296 (encapsulation solvent manufactured by Nippon Petrochemical) under heating. 10 parts of a system modifier was added to 200 parts of water, and the pH was adjusted to 4 with an aqueous solution of caustic soda. The above solution and 20 parts of melamine formaldehyde prepolymer were added thereto, and the mixture was emulsified with a homomixer until oil droplets became 4 μm. Then, the mixture was heated to 60 ° C. with stirring and stirred for 1 hour. After cooling to room temperature, the pH was adjusted to 7.5 with 25% aqueous ammonia to prepare a capsule dispersion of the leuco dye.

The capsule dispersion liquid 1 thus prepared
After 0 parts, 2 parts of flour starch and 1 part of latex were mixed well, the amount of solids applied to fine paper of 50 g / m ² basis weight was 5%.
g / m ² to form an upper sheet.

The upper sheet created in this way is 3,5-
When the lower paper coated with zinc di (1-phenylethyl) salicylate was overlapped with the coated surface so as to be in contact with the lower paper and type-printed, a clear pure black recorded image was formed on the lower paper. This recorded image was adapted for OCR reading using a wavelength of 780 nm or 820 nm.

Example 5 Production of pressure-sensitive recording medium 2- (2,6-dimethylanilino) -3-methyl-6-
3 parts of diethylaminofluoran, 3 parts of 2- (2,4-dimethylanilino) -3-methyl-6-diethylaminofluoran, 3 parts of 2-chloro-3-methyl-6- [4- (4-
Anilinoanilino) anilino] fluorane (3 parts) and 3,3-bis (1-n-butyl-2-methyl-3-indolyl) phthalide (1 part) were heated under heating to 115 parts of SAS-296 (encapsulated solvent manufactured by Nippon Petrochemical). Dissolved. Water 2
To 10 parts of the system modifier was added 10 parts, and p
H4. The above solution and 20 parts of melamine formaldehyde prepolymer were added thereto, and the mixture was emulsified with a homomixer until oil droplets became 4 μm. Then, the mixture was heated to 60 ° C. with stirring and stirred for 1 hour. After cooling to room temperature, 25
The pH was adjusted to 7.5 with aqueous ammonia to prepare a capsule dispersion of the leuco dye.

The capsule dispersion liquid 1 thus prepared
After 0 parts, 2 parts of flour starch and 1 part of latex were mixed well, the amount of solids applied to fine paper of 50 g / m ² basis weight was 5%.
g / m ² to form an upper sheet.

The upper sheet created in this way is 3,5-
When the lower paper coated with zinc di (1-phenylethyl) salicylate was overlapped with the coated surface so as to be in contact with the lower paper and type-printed, a clear pure black recorded image was formed on the lower paper. This recorded image was adapted for OCR reading using a wavelength of 900 nm.

[0039]

According to the present invention, the color tone of the recorded image is pure black,
An object of the present invention is to provide a pressure-sensitive recording medium having a small red discoloration degree of the black recorded image.

Continuation of the front page (72) Inventor Mansuke Matsumoto 1-43, Yuge-cho Minami, Yao-shi, Osaka Yamamoto Kasei Co., Ltd. (56) References JP-A-1-150574 (JP, A) JP 49-32767 (JP, B2) JP 49-17490 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/124-5/165

Claims (3)

(57) [Claims] 1. A pressure-sensitive recording material utilizing a color development reaction between an electron-donating leuco dye and an electron-accepting developer, wherein 2- (2,6-dimethylanilino) -3- is used as the electron-donating leuco dye. Methyl-6-diethylaminofluoran and 2
A pressure-sensitive recording material, which comprises using-(2,4-dimethylanilino) -3-methyl-6-diethylaminofluoran in combination. 2. A pressure-sensitive recording medium utilizing a color development reaction between an electron-donating leuco dye and an electron-accepting developer, wherein 2- (2,6-dimethylanilino) -3- is used as the electron-donating leuco dye. 2. A pressure-sensitive recording material according to claim 1, wherein methyl-6-diethylaminofluoran is used in an amount of 20 to 80% by weight of the total electron donating leuco dye. 3. A pressure-sensitive recording medium utilizing a color-forming reaction between an electron-donating leuco dye and an electron-accepting developer, wherein the electron-donating leuco dye is encapsulated in microcapsules. 3. The pressure-sensitive recording medium according to 1 or 2.